NAIROBI - Kenya's president said his forces had "defeated" Islamists from Somalia's al Shabaab on Tuesday, shooting dead five and capturing 11 others suspected of killing 67 people during a four-day siege at a shopping mall.

"The operation is now over," Uhuru Kenyatta told Kenyans in a televised address, adding that more bodies, seemingly both gunmen and hostages, remained under rubble after three floors in part of the Westgate centre collapsed late in the mission.

"We have ashamed and defeated our attackers," he said.

Police said those who stormed into restaurants and shops at a busy lunchtime on Saturday, spraying bullets and grenades, were now either dead or in custody: "Now it is for the forensic and criminal experts," said a police spokesman, Masoud Mwinyi.

The Red Cross said earlier on Tuesday that 63 people were unaccounted for. About 60 civilians were already confirmed dead in the first days of violence. Kenyan officials declined to say late on Tuesday how many more may have died later, with gunmen who had vowed to kill hostages and go down fighting if attacked.

It also remained unclear who the attackers were, beyond their loyalty to al Qaeda-linked al Shabaab, which had demanded Kenya pull troops out of Somalia. The president said he could not confirm they included two or three Americans or a British woman who might be the widow of a London suicide bomber.

However, al Shabaab themselves, on Twitter, denied that any women took part. After days of trumpeting defiance on behalf of those holding out in the mall, however, the group's silence on their fate late on Tuesday suggested their mission had ended.

"There are several bodies trapped in the rubble, including the terrorists," Kenyatta said. He put the confirmed death toll so far at 61 civilians and six security personnel, as well as five of the militants. The official toll previously stood at 62.

Officials said the gunmen had set a major fire on Monday in a supermarket. On Tuesday, a thin trail of smoke drifted into a soggy sky as darkness fell, the result, rescue volunteers said, of soldiers detonating locked doors in a search for militants.

Police were letting some people retrieve cars left behind when shoppers fled in panic as gunmen, whom officials had said numbered about a dozen or more, burst upon them. But journalists and others were still kept well away behind a security cordon.

FOREIGNERS

The president said he could not confirm intelligence reports of British and American militants, adding that forensic tests were being carried out to establish their nationalities. On Monday, the government denied speculation of women being among the guerrillas, but said some had been dressed as women. That may have been a ploy to smuggle more weapons past mall guards.

It would be unusual for Islamist militants to put women on the frontline and al Shabaab categorically denied it. British media have speculated about the involvement of the "White Widow", the fugitive British wife of one of the four men who blew themselves up in the 7/7 bombings in London in July 2005.

"We have an adequate number of young men who are fully committed & we do not employ our sisters in such military operations #Westgate," al Shabaab said on its Twitter feed.

Making no mention of gunmen still in the mall, it also drew a link to the most recent Islamist attack in London, when a soldier was stabbed death on a busy street in May in the suburb of Woolwich. Michael Adebolajo and a fellow British Muslim convert of Nigerian descent face trial for murder.

"It's an eye for an eye and a tooth for a tooth...' Remember Mujahid Adebolajo? This is what he meant. His was #Woolwich, #Westgate ours!" another al Shabaab Twitter post read.

Kenyatta said: "These cowards will meet justice as will their accomplices and patrons, wherever they are."

KENYATTA

He thanked other leaders, including U.S. President Barack Obama, for support and used his address to both praise the response of the Kenyan people and call for national unity, six months after his election was marked by ethnic tensions.

"Kenya has stared down evil and triumphed," he said.

Kenyatta's focus on Kenya's troubles, and of his role in a global campaign against terrorism, was a reminder that he faces trial at The Hague in a few weeks time for crimes against humanity over violence that followed a previous election, in 2007. The International Criminal Court adjourned the trial of his vice president this week because of the Westgate crisis.

The president and his government have urged the ICC to drop the case and warm words for the Kenyan leadership from Western allies during the siege may have encouraged their hopes that the court might be pressed to shelve proceedings in the interests of shoring up an important partner in the fight against al-Qaida.

The attack has come at a time when several violent Islamist groups from Mali to Algeria, Nigeria to Kenya - tapping into local grievances but all espousing an anti-Western, anti-Christian creed - are striking at state authority and international interests.

Kenyatta had rejected demands that he pull Kenyan troops out of its northern neighbour. As part of an African peacekeeping force in Somalia, those soldiers have pushed al Shabaab on to the defensive over the past two years.

Its attack on an Israeli-built complex that symbolized the rise of an affluent class of Africans alongside expatriate Westerns may now help the movement to a position of prominence in the widening constellation of international jihadists.

Images from closed-circuit television inside the mall during the attack showed two militants, casually dressed and wearing ammunition belts. One held an assault rifle. Al Shabaab confirmed he pair were part of the group that attacked Westgate.

Kenyan Foreign Minister Amina Mohamed said earlier that "two or three Americans" and a British woman were among the militants. She said the Americans were "young men, about between maybe 18 and 19" years old. She said they were of Somali or Arab origin and had lived in "in Minnesota and one other place".

Al Shabaab, which said it had been in communication with its members in the mall, dismissed the minister's comments.

'WHITE WIDOW?'

A British security source said it was possible that Samantha Lewthwaite, widow of 7/7 bomber Germaine Lindsay, was involved in the Nairobi siege in some way. "It is a possibility. But nothing definitive or conclusive yet," the source said.

Lewthwaite is thought to have left Britain several years ago and is wanted in connection with an alleged plot to attack expensive hotels and restaurants in Kenya.

President Obama, whose father was Kenyan, said he believed the country - scene of one of al-Qaida's first big attacks, in 1998 - would continue to be a regional pillar of stability.

Somalia's prime minister appealed in Geneva on Tuesday for international support to combat al Shabaab but said a military solution to their insurgency alone was not enough.

Abdi Farah Shirdon said: "We still have a difficult journey ahead of us. A military solution alone is not enough, promotion of rule of law, greater regional cooperation and economic stability and provision of public services are all key factors."

British Defence Secretary Philip Hammond said he believed six Britons had died in the attack. Other known foreign victims are from China, Ghana, France, the Netherlands and Canada.